Comfort: low muscle tension thanks to a released position of fingers and wrist.
Six models: right and left; 3 sizes: distance between the wrist (the junction between the hand and the arm) and the end of the ring: up to 170 mm: Small (small), 170 - 190 mm: Medium (middle) and 190 -210 mm: Large (large).
Practice: 2 buttons in ergonomic position and a scroller.